This invention relates to gas regulators and more particularly to an oxygen gas regulator adapted to dispense therapeutic oxygen at a controlled pressure.
Oxygen gas is used widely in treating human medical conditions. Oxygen gas is dispensed in hospitals, emergency response vehicles and other locations when dealing with critical situations. Oxygen gas is also dispensed in treating chronic conditions such as emphysema. Oxygen gas must be dispensed at a controlled pressure and flow rate in these applications. Moreover, the oxygen gas is often dispensed in mobile environments such as emergency vehicles, the home or from portable dispensers used by persons with chronic conditions. The dispensers must be rugged, light and easy to use. One way of addressing this need is the dispensing of oxygen gas from containers, sometimes referred to as tanks or bottles, which are relatively small and hold oxygen gas under high pressure, e.g., 2000-3000 psi. The oxygen gas containers are provided with an outlet of conventional design and an on/off valve. A regulator is applied to the outlet, the tank valve opened and oxygen provided through the regulator to a regulator output. The regulator provides oxygen at a desired pressure and flow rate at its output. Some such regulators have a variable outlet flow rate.
The described regulators work reasonably well. However, improvements are desired.
Oxygen therapy is used by a wide variety of people and therefore oxygen regulators must be easy to use and understand. Oxygen gas regulators are used in mobile environments and therefore subject to mechanical shock, unintended impact and the like. Oxygen regulators must therefore be robust.
It is desirable that oxygen regulators have a consistent repeatable output pressure for their intended flow range. If a physician prescribes a particular oxygen supplementation level, such a prescription can only be followed if the person setting up the oxygen supply can rely upon the stated output parameters of a regulator.
Oxygen regulators need to be inexpensive to manufacture and easy to maintain.
Prior art regulators which are appropriate for use in the medical dispensing of oxygen gas, especially mobile dispensing, have a relatively broad variation of output parameters from one regulator to the next. Some prior art regulators are big, heavy and subject to damage. Other prior art regulators are expensive. Other prior art regulators require maintenance or adjustment which are beyond the capacity of many users.
The above described requirements are achieved and the problems overcome in the present invention in which a small oxygen gas regulator is provided with an array of five biasing springs rather than a single biasing spring.
In accordance with the present invention, there is provided an oxygen gas regulator comprising a regulator body having an inlet receiving oxygen from an oxygen tank, an upper chamber receiving gas from the gas inlet, a lower chamber, a gas outlet receiving gas from the lower chamber, a passage from the upper chamber to the lower chamber, a movable piston having a low pressure surface exposed in the lower chamber and an atmospheric surface exposed to atmospheric pressure, an orifice controlling flow of gas into the upper chamber, the orifice being controlled by the piston, and five biasing springs urging the piston toward the lower chamber.
Yet further in accordance with the invention, the five biasing springs are evenly spaced around a circle which is concentric with the axis of the piston.
Still further in accordance with the invention, the five biasing springs are received in pockets in a support which is immovable with respect to the valve body.
Still further in accordance with the invention, the five biasing springs are small coil springs having identical nominal spring rates.
It is the principal object of the present invention to provide an oxygen gas regulator which is inexpensive to manufacture, easy to maintain and provides more uniform output parameters than conventional regulators.
It is yet another object of the present invention to provide a gas regulator in which variations in output parameters due to variations in part parameters, e.g., spring characteristics, is minimized.
It is yet another object of the present invention to provide an oxygen gas regulator which maintains output characteristics over its design range.
It is still another object of the present invention to provide an oxygen gas regulator which delivers oxygen gas at the desired pressure and flow rate over a broad range of gas input pressures.
It is yet another object of the present invention to provide an oxygen gas regulator requiring only minimal maintenance.
It is still another object of the present invention to provide an oxygen gas regulator requiring only minimal field calibration.
It is still another object of the present invention to provide an oxygen gas regulator which is robust, small, easy to use, and lightweight.